Treatment device and treatment method for wastewater containing organic matter

Abstract

To treat a persistent organic matter in water at a low cost and low energy cost, reducing ecotoxicity.SOLUTION: A wastewater treatment device (1) of the present disclosure includes: a tank (50) for storing wastewater; a composite sheet (10) containing titanium oxide and zeolite; a rotating drum (20) with the composite sheet (10) attached to its surface, arranged so that a portion of a surface of the composite sheet is immersed in water and a portion is above a water surface while water is stored in the tank (50); a motor (40) for rotating the rotating drum (20) while maintaining a state in which a portion of the surface of the composite sheet (10) is immersed in water and a portion is above the water surface, with water stored in the tank (50); and an ultraviolet light source (30, 31 to 35) for irradiating ultraviolet light onto the composite sheet (10) on the water surface in a direction including a direction perpendicular to the surface of the composite sheet (10).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus and method for treating wastewater containing organic matter, and the apparatus and method for treating wastewater of the present disclosure are particularly suitable for treating wastewater containing persistent organic matter using an advanced oxidation process. [Background technology]

[0002] Advanced oxidation is a known technology for removing persistent organic matter from wastewater. This method uses photocatalysts such as titanium oxide to decompose the persistent organic matter in wastewater. Photocatalysts such as titanium oxide generate reactive oxygen species under sunlight irradiation, which can decompose the persistent organic matter, so photocatalytic decomposition is expected to be an energy-saving advanced oxidation method.

[0003] However, the advanced oxidation process also faces challenges, such as reaction inhibition due to coexisting substances in wastewater and a decline in treatment performance due to attenuation of transmitted light in water as the process scales up. There is a need for the development of a photocatalytic device that can overcome these challenges. To address these challenges, the inventors have developed a sheet catalyst that combines titanium oxide and high-silica zeolite, and have proposed its use in the advanced oxidation process (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Y. Nomura et al., J. Water Process Eng., 48 (2022) 102936. Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional advanced oxidation methods have had issues such as reaction inhibition due to coexisting substances in the wastewater and insufficient treatment performance due to insufficient light being supplied to the photocatalyst. [Means for solving the problem]

[0006] A first wastewater treatment device of the present disclosure is a treatment device for wastewater containing organic matter, a tank for storing wastewater; a composite sheet containing titanium oxide and zeolite; a rotating drum having the composite sheet attached to its surface, the rotating drum being positioned such that a portion of the surface of the sheet is immersed in the water and a portion is above the water surface when water is stored in the tank; a motor that rotates the rotating drum while maintaining a state in which a portion of the surface of the composite sheet is immersed in water and a portion is above the water surface with water stored in the tank; The apparatus further includes an ultraviolet light source that irradiates ultraviolet light onto the composite sheet resting on the water surface in a direction including a direction perpendicular to the surface of the composite sheet.

[0007] The wastewater treatment method of the present disclosure is a method for treating wastewater containing organic matter using a titanium oxide-zeolite composite sheet, comprising: (a) immersing a composite sheet in wastewater containing organic matter; (b) after step (a), irradiating the composite sheet having moisture thereon with ultraviolet light in the atmosphere from a direction including a direction perpendicular to the surface of the composite sheet; (c) after the step (b), and before immersing the composite sheet again in the wastewater containing the organic matter, a step (c) of irradiating the composite sheet with moisture with ultraviolet light from a direction including a direction perpendicular to the surface of the composite sheet; Includes. [Effects of the Invention]

[0008] In the wastewater treatment device disclosed herein, a composite sheet containing titanium oxide and zeolite is attached to the surface of a rotating drum, the composite sheet moves through water and the atmosphere, and while in the atmosphere, ultraviolet light is irradiated from directions including perpendicular to the surface of the composite sheet. This allows the catalytic function of the composite sheet to be efficiently utilized by the ultraviolet light, allowing efficient decomposition of organic matter and reduced ecotoxicity. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view of a wastewater treatment device 1 (RAOC) of the present embodiment. [Figure 2] FIG. 2 is a schematic side view illustrating ultraviolet irradiation efficiency in the wastewater treatment device 1a of the reference example. [Figure 3] FIG. 2 is a schematic side view illustrating ultraviolet irradiation efficiency in the wastewater treatment device 1 of the present embodiment. [Figure 4] FIG. 2 is a diagram for schematically explaining how hydrophobic pharmaceuticals in wastewater are decomposed in the wastewater treatment device 1 of this embodiment. [Figure 5] This figure shows the amount of SMT (mg) in the treated water, the amount of SMT (mg) in the composite sheet, and the amount of SMT (mg) in the combined treated water and composite sheet as a function of treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment device 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. The UV dose (UV Dose (MJ / cm2)) is shown above the horizontal axis. [Figure 6] This figure shows the biodegradation inhibition rate (%) and the treatment time dependence (h) of the total organic carbon concentration (TOC concentration (PPM)) in the treated water when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment apparatus 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. The upper part of the horizontal axis shows the input energy for UV irradiation (ultraviolet irradiation dose (MJ / cm2)). [Figure 7] FIG. 1 shows the growth inhibition rate (%) of samples (on the horizontal axis, A indicates dark conditions, D indicates light conditions, and the numbers indicate the treatment time under each condition) at the time of treatment with a sulfamethazine solution (SMT solution) for 107 hours in wastewater treatment device 1 (RAOC) in Example 1 (using a titanium oxide-zeolite composite sheet, TiO2-Zeolite composite sheet) and Comparative Example 1 (using a titanium oxide sheet, TiO2-Only sheet). [Figure 8A]This figure shows the dependence of the amount of SMT-OH in the treated water, the amount of SMT-OH in the composite sheet, and the amount of SMT-OH in the combined system of the treated water and the composite sheet on treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment device 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. For the treatment time dependence, the start time of the light treatment is set to 0. The amount of SMT-OH is a value normalized by the maximum value (peak area ratio). [Figure 8B] This figure shows the dependence of the ADMP amount in the treated water, the ADMP amount in the composite sheet, and the ADMP amount in the combined system of the treated water and the composite sheet on treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment device 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. For the treatment time dependence, the start time of the light treatment is set to 0. The ADMP amount is a value normalized by the maximum value (peak area ratio). [Figure 8C] This figure shows the dependence of the amount of ADMP-OH in the treated water, the amount of ADMP-OH in the composite sheet, and the amount of ADMP-OH in the combined system of the treated water and the composite sheet on treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment device 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. For the treatment time dependence, the start time of the light treatment is set to 0. The amount of ADMP-OH is a value normalized by the maximum value (peak area ratio). [Figure 8D] This figure shows the dependence of p-AP amounts in the treated water, the composite sheet, and the combined system of the treated water and the composite sheet on treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment device 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. For the treatment time dependence, the start time of the light treatment is set to 0. The p-AP amount is a value normalized by the maximum value (peak area ratio). [Figure 9]This figure shows the dependence of the ADMP concentration and p-AP concentration (mg / L) in treated water on the treatment time (h) when a sulfamethazine solution (SMT solution) was treated in a wastewater treatment apparatus 1 (RAOC) using a titanium oxide-zeolite composite sheet 10 in Example 1. The start time of the light treatment is set to 0 for the treatment time dependence. [Figure 10A] 1 is a dose-response curve for sulfamethazine (SMT). [Figure 10B] 1 is a dose-response curve for ADMP. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure relates to the treatment of wastewater containing organic matter using an advanced oxidation process. The wastewater includes wastewater from livestock farming, aquaculture facilities, medical facilities, and urban sewage. The organic matter is particularly persistent organic matter and / or pharmaceuticals. The pharmaceuticals are particularly antibiotics.

[0011] (1) Titanium oxide zeolite composite sheet The advanced oxidation method of the present disclosure uses a titanium oxide-zeolite composite sheet 10. The zeolite in the titanium oxide-zeolite composite sheet 10 is a high-silica zeolite. The high-silica zeolite has, for example, an SiO2 / Al2O3 ratio of 100. The SiO2 / Al2O3 ratio may be 50 or more and 200 or less. High-silica zeolite powder has the property of selectively adsorbing sulfa-based antibacterial agents in wastewater. However, high-silica zeolite powder has the problem that its adsorption function decreases when saturated adsorption is reached.

[0012] Titanium oxide (TiO2) is a typical photocatalyst. Titanium oxide catalysts can decompose difficult-to-decompose organic matter when irradiated with ultraviolet light. However, titanium oxide powder catalysts have the disadvantage that the reaction can be inhibited by coexisting substances in wastewater.

[0013] Therefore, in this embodiment, by using a zeolite / titanium oxide composite catalyst, the shortcomings of zeolite powder and titanium oxide powder can be compensated for. In the composite catalyst, hydrophobic organic chemicals are first adsorbed by the zeolite. The organic chemicals desorbed by the zeolite then move to the titanium oxide and are decomposed by ultraviolet light. In this way, adsorption / desorption and decomposition occur continuously, enabling sustainable treatment of organic chemicals.

[0014] In this embodiment, a titanium oxide-zeolite composite sheet 10 is used instead of powders such as zeolite powder or titanium oxide powder. The titanium oxide-zeolite composite sheet is composed of titanium oxide powder, zeolite powder, and fibers. Fibers, binders, and other additives are added to the titanium oxide powder and zeolite powder, and a titanium oxide-zeolite composite sheet is produced using papermaking techniques. The thickness of the titanium oxide-zeolite composite sheet 10 is 0.1 mm or more and 1.0 mm or less. The titanium oxide-zeolite composite sheet 10 may be used alone, in a stack of two sheets, or in a stack of three or more sheets. Whether two or three or more sheets are used, the thickness of each titanium oxide-zeolite composite sheet 10 is 0.1 mm or more and 1.0 mm or less. The titanium oxide-zeolite composite sheet 10 has many voids. Furthermore, the titanium oxide-zeolite composite sheet 10 has water retention properties.

[0015] (2) Rotating Drum Advanced Oxidation Unit (RAOC) A schematic configuration of a wastewater treatment device 1 of this embodiment is shown in FIG. 1. The wastewater treatment device 1 is a rotating drum type advanced oxidation device. In this specification, the wastewater treatment device 1 may also be referred to as a Rotating Advanced Oxidation Contactor (RAOC). Treatment of wastewater (water in which chemical substances are dissolved for experimental purposes may be referred to as wastewater or treated water) using the wastewater treatment device 1 may also be referred to as RAOC treatment.

[0016] The wastewater treatment device 1 includes a tank 50, a titanium oxide / zeolite composite sheet 10, a rotary drum 20, a motor 40, and ultraviolet light sources 31-35.

[0017] The tank 50 stores the wastewater to be treated. A rotating drum 20, with a titanium oxide-zeolite composite sheet 10 attached to the outer cylindrical surface, is immersed in the wastewater in the tank 50. The rotating drum 20 may be hollow to allow the wastewater to enter the interior, as shown in FIG. 1, or may be sealed to prevent the wastewater from entering the interior. The rotating drum 20 is positioned so that 10% to 80% of its cylindrical surface is immersed in the wastewater. The rotating drum 20 may also be positioned so that 20% to 50% of its cylindrical surface is immersed in the wastewater. A larger portion of the rotating drum 20 is exposed above the water surface, ensuring a larger area on the titanium oxide-zeolite composite sheet 10 that is irradiated with ultraviolet light.

[0018] To accommodate larger sizes, the rotating drum 20 has a cylindrical diameter of 20 cm or more, preferably 50 cm or more. There is no particular upper limit, but depending on the size of the treatment tank 50, the cylindrical diameter is, for example, 5 m or less.

[0019] A motor 40 for rotating the rotary drum 20 is attached to the rotary shaft of the rotary drum 20. The motor 40 rotates the rotary drum 20, which is immersed in wastewater. The rotation speed of the rotary drum 20 during wastewater treatment is, for example, 10 rpm. The rotation speed may be 1 rpm or more and 25 rpm or less.

[0020] In the wastewater treatment device 1, ultraviolet light sources 31-35 are arranged to irradiate ultraviolet light onto the titanium oxide-zeolite composite sheet 10 above the water surface. The reason for irradiating ultraviolet light onto the titanium oxide-zeolite composite sheet 10 above the water surface is that ultraviolet light effectively acts on the catalyst. Conversely, irradiating ultraviolet light onto the titanium oxide-zeolite composite sheet 10 while it is underwater does not sufficiently decompose organic matter. The number of ultraviolet light sources 31-35 may be five. The number of ultraviolet light sources 31-35 may be one to ten. The above numbers apply when one ultraviolet light source corresponds to one rotation angle of the rotating drum 20. When the width of the rotating drum (the length corresponding to the height of the cylinder of the rotating drum) is long, multiple ultraviolet light sources may be arranged for one rotation angle of the rotating drum 20. In FIG. 1, each ultraviolet light source 31-35 is arranged to irradiate ultraviolet light onto the surface of the titanium oxide-zeolite composite sheet 10 from directions including the vertical direction. The ultraviolet light sources 31 to 35 are configured to irradiate the titanium oxide-zeolite composite sheet 10 with ultraviolet light at different rotation angles of the rotary drum 20.

[0021] Here, the excellent efficiency of ultraviolet irradiation in the wastewater treatment device 1 of this embodiment will be described with reference to the drawings. Fig. 2 shows a wastewater treatment device 1a of a reference example, and Fig. 3 shows the wastewater treatment device 1 of the present disclosure.

[0022] In the wastewater treatment device 1a of Reference Example 1a, as shown in Fig. 2, wastewater is stored in a tank 50a, and multiple disks 21, each with a titanium oxide-zeolite composite sheet 10a attached to its surface, rotate with a portion of the disk 21 immersed in the wastewater. The reason for arranging multiple disks 21 is to treat a large amount of wastewater in a short period of time. The portions of the titanium oxide-zeolite composite sheet 10a of the disks 21 exposed to the atmosphere are irradiated with ultraviolet light from an ultraviolet light source 30a. However, with the configuration of Fig. 2, it is difficult to irradiate most of the titanium oxide-zeolite composite sheet 10a with ultraviolet light from a substantially vertical direction in the atmosphere.

[0023] In contrast, in the wastewater treatment device 1 of this embodiment, the titanium oxide-zeolite composite sheet 10 is attached to the cylindrical surface of the rotating drum 20, and ultraviolet light is irradiated from the ultraviolet light source 30. This allows ultraviolet light to be irradiated from a substantially perpendicular direction onto the surface of many of the titanium oxide-zeolite composite sheets 10, activating the catalytic reaction. Furthermore, by arranging multiple ultraviolet light sources 30a at different rotation angles of the rotating drum 20 as shown in Figure 3, the same portion of the titanium oxide-zeolite composite sheet 10 will be irradiated with ultraviolet light multiple times while it is in the air while immersed in water, potentially enabling a multi-stage catalytic reaction to occur effectively.

[0024] Next, the mechanism by which trace chemical substances (hydrophobic pharmaceuticals) in wastewater are decomposed in the wastewater treatment device 1 of this embodiment will be described with reference to the drawings. Figure 4 is a diagram that schematically illustrates how a hydrophobic pharmaceutical is decomposed in water.

[0025] First, a hydrophobic drug (parent substance) (A1) in water is adsorbed to the titanium oxide-zeolite composite sheet 10 by the action of the zeolite in the composite sheet 10 (A2). The hydrophobic drug (A2) adsorbed to the composite sheet 10 moves into the atmosphere as the rotating drum 20 rotates, where it is decomposed into hydrophobic decomposition products (daughter substances) by irradiation with ultraviolet light from ultraviolet light sources 31, 32, etc. (A3). The hydrophobic decomposition products are further decomposed into hydrophilic decomposition products (daughter substances) by irradiation with ultraviolet light from ultraviolet light sources 33, 34, etc. as the rotating drum 20 rotates (A4). The hydrophilic decomposition products move into the water as the rotating drum 20 rotates (A5). The hydrophilic decomposition products in the wastewater dissolve in the water and diffuse into the water. As described above, the wastewater treatment device 1 of this embodiment can selectively remove hydrophobic drugs (parent substances) from the wastewater and convert them into hydrophilic decomposition products.

[0026] (Example) In order to confirm the wastewater treatment effect of the wastewater treatment device 1 of this embodiment, experiments of Example 1 and Comparative Example 1 were carried out as follows.

[0027] First, a sulfamethazine solution (SMT solution) was prepared as wastewater containing organic matter. Sulfomethazine (SMT) is a persistent organic substance and a synthetic antibacterial agent. The initial concentration of SMT in the SMT solution was 10 mg / L, the volume of the SMT solution was 100 L, and the mass was 1,000 mg.

[0028] In Example 1, the titanium oxide-zeolite composite sheet 10 was prepared by adding fibers, binders, etc. to titanium oxide (manufactured by Nippon Aerosil Co., Ltd.) and high-silica zeolite (HSZ-385, manufactured by Tosoh Corporation), and forming the sheet using papermaking techniques. In Comparative Example 1, a titanium oxide sheet was also prepared using papermaking techniques using only titanium oxide without using zeolite. The titanium oxide-zeolite composite sheet 10 of Example 1 or the titanium oxide sheet of Comparative Example 1 was fixed to the cylindrical surface of the rotating drum 20 of the wastewater treatment device 1, and each experiment was conducted.

[0029] Using the wastewater treatment device 1, the SMT solutions of Example 1 and Comparative Example 1 were treated for 107 hours. From the first 0 to 21 hours, the rotating drum 20 was simply rotated without UV irradiation (dark conditions), and from the next 21 to 107 hours, the rotating drum 20 was rotated while UV irradiation was performed (light conditions). The UV irradiation dose was 1 mW / cm. 2 is.

[0030] After a predetermined time, the treated water and sheet samples were collected to investigate the dynamics of SMT and degradation products during treatment, and the biodegradability and ecotoxicity of the treated water were evaluated. To assess the biodegradability of the treated water, the biochemical oxygen demand (BOD5) of a model organic solution (glucose and glutamic acid) was measured to evaluate the biodegradation inhibition rate. The ecotoxicity evaluation test of the treated water was conducted in accordance with the OECD (Organization for Economic Co-operation and Development) guidelines. The microalgae Scenedesmus Obliquus (NIES-2280 strain) was cultured in the culture medium for 96 hours, and the growth rate was evaluated based on the change in biomass weight over time. Three types of culture medium were used: treated water from Example 1 using a titanium dioxide-zeolite composite sheet, treated water from Comparative Example 1 using a titanium dioxide sheet, and ultrapure water (blank). The growth inhibition rate was evaluated based on the growth rate (algae biomass growth) of the microalgae from Example 1 and Comparative Example 1.

[0031] (Evaluation results) The behavior of SMT during RAOC treatment using the titanium dioxide-zeolite composite sheet of Example 1 is shown in Figure 5. Figure 5 confirms that under dark conditions, the amount of SMT in the treated water decreased due to adsorption by the composite sheet, while the amount of SMT in the composite sheet increased, with the amount of SMT in the system remaining unchanged from the initial state. After 21 hours, when ultraviolet light was irradiated (under light conditions), a tendency for the amount of SMT in the sheet and the amount of SMT in the system to decrease was confirmed, indicating that decomposition products were being generated by photocatalytic decomposition of SMT.

[0032] Previous research by the inventors has revealed the following trends regarding high-silica zeolite HSZ-385: High-silica zeolite HSZ-385 adsorbs organic matter in water through hydrophobic interactions. Hydrophobic decomposition products are adsorbed by high-silica zeolite HSZ-385. Hydrophilic decomposition products generated by the decomposition of hydrophobic biodegradable organisms are not adsorbed by high-silica zeolite HSZ-385 and are released into the treated water.

[0033] As shown in Figure 6, under dark conditions, the total organic carbon (TOC) concentration in the treated water decreased due to adsorption and removal of SMT. Under light conditions, hydrophilic degradation products were generated and released into the treated water as SMT and hydrophobic degradation products decomposed. This resulted in an increase in TOC concentration. BOD5 represents the oxygen consumption during organic matter decomposition by aerobic microorganisms after 5 days of incubation at 20°C. A positive value for the inhibition on BOD5 indicates that SMT and degradation products inhibit the decomposition of organic matter by aerobic microorganisms. Conversely, a negative value indicates no inhibition of organic matter decomposition by aerobic microorganisms. The biodegradation inhibition rate for 10 mg / L SMT was approximately 18%, confirming that SMT inhibits biodegradation. Under dark conditions, the amount of SMT in the treated water decreased due to adsorption, and the biodegradation inhibition rate decreased, reaching zero after 21 hours of treatment. Under light conditions, an increase in the TOC concentration of the treated water was confirmed due to the release of hydrophilic organic matter, while the biodegradation inhibition rate continued to decline below 0, reaching -12% after 69 hours of treatment. This demonstrates that the RAOC treatment of Example 1 using a titanium dioxide-zeolite composite sheet in the treatment of SMT converts SMT into biodegradable degradation products, thereby improving the biodegradability of the treated water.

[0034] Next, the microalga Scenedesmus Obliquus was cultured using the treated water from Example 1 and Comparative Example 1. The ecotoxicity of the treated water from Example 1 and Comparative Example 1 was evaluated based on the growth inhibition rate relative to the blank. As shown in A0 (treatment time 0 h) in Figure 7, the algae growth inhibition rate by 10 mg / L SMT before RAOC treatment was approximately 55%.

[0035] The results of RAOC treatment in Comparative Example 1 using a titanium dioxide sheet are as follows (Inhibition-TiO2-Only sheet in Figure 7). Because titanium dioxide does not adsorb SMT under dark conditions, the growth inhibition rate did not decrease and remained equivalent to the initial A0 (0 h). Under light conditions, the growth inhibition rate decreased over the 6-h treatment time (D6) as SMT decomposed, but in addition to showing a growth inhibition rate of approximately 35%, it increased to 50% over the 24-h treatment time (D24), revealing that ecotoxic decomposition products were produced during the photocatalytic decomposition of SMT. As the photocatalytic decomposition of the ecotoxic decomposition products continued, the growth inhibition rate gradually decreased, reaching 5% after 96 h.

[0036] On the other hand, the results of the RAOC treatment in Example 1 using a titanium oxide-zeolite composite sheet are as follows (Inhibition-TiO2-Zeolite composite sheet in Figure 7). Under dark conditions (A0 to D0), the growth inhibition rate decreased with adsorption of SMT, reaching 10% after 12 hours (D0). Under light conditions (D0 to D6), the growth inhibition rate remained around 15%. While the RAOC treatment in Comparative Example 1, which was equipped with a titanium oxide sheet, showed a growth inhibition rate of approximately 35%, it was clear that the growth inhibition rate in Example 1 was lower. It was clear that the RAOC treatment in Example 1 using a titanium oxide-zeolite composite sheet was able to reduce ecotoxicity caused by decomposition products.

[0037] Analysis of decomposition products during RAOC treatment of SMT in Example 1 using a titanium dioxide-zeolite composite sheet revealed four substances. These four substances are SMT-OH, which is formed by the hydroxide of the aromatic ring of SMT; ADMP, which is formed by the cleavage of SMT-OH; ADMP-OH, which is formed by the hydroxylation of ADMP; and 4-aminophenol (p-AP), which is formed by the cleavage of the sulfadoamino group of SMT. Figures 8A-8D show the RAOC treatment time dependence of the amounts of these four substances in the treated water, the sheet, and the entire system including the treated water and the sheet. As shown in Figures 8A-8D, all substances were confirmed to be present within the sheet, indicating that they are decomposition products adsorbed by high-silica zeolite. SMT-OH and ADMP were detected at higher intensities within the sheet than in the treated water, while ADMP-OH and p-AP were detected at higher intensities in the treated water. Therefore, the concentrations of ADMP and p-AP in the treated water were quantified using standard standards.

[0038] As a result of standard quantification, as shown in Figure 9, it was confirmed that the p-AP concentration in the treated water reached a maximum after 12 hours under light conditions, and the ADMP concentration in the treated water reached a maximum after 36 hours under light conditions, and then decreased.

[0039] Next, we investigated the relationship between growth inhibition rates and SMT and ADMP concentrations, and calculated the median effective concentration (EC50) values ​​from the dose-response curves. As shown in Figures 10A and 10B, the EC50 values ​​for SMT and ADMP were 1.47 mg / L and 0.295 mg / L, respectively, indicating that ADMP has higher ecotoxicity than SMT. The growth inhibition rates for the titanium dioxide-zeolite composite sheet shown in Figure 7 roughly correspond to the behavior of the ADMP concentration in the treated water shown in Figure 9. Therefore, the increase in growth inhibition rate for the titanium dioxide-zeolite composite sheet at D6 to D36 in Figure 7 is likely due to ADMP. It was revealed that the RAOC of the example using the titanium dioxide-zeolite composite sheet can reduce the ecotoxicity of treated water by adsorbing and retaining highly ecotoxic decomposition products such as ADMP within the sheet while decomposing them.

[0040] (3) Features of this embodiment The wastewater treatment device 1 of this embodiment includes a tank 50 for storing wastewater containing organic matter, a titanium oxide zeolite composite sheet 10, and a rotating drum 20 with the composite sheet 10 attached to its surface, the rotating drum 20 being positioned so that when water is stored in the tank 50, part of the surface of the composite sheet 10 is immersed in the water and part is above the water surface, a motor 40 for rotating the rotating drum 20 while maintaining part of the surface of the composite sheet 10 immersed in the water and partly above the water surface when water is stored in the tank 50, and ultraviolet light sources 30, 31 to 35 for irradiating ultraviolet light onto the composite sheet 10 above the water surface from a direction including the vertical direction to the surface of the composite sheet 10.

[0041] In the present disclosure, wastewater containing organic matter to be treated is particularly difficult-to-decompose organic matter and / or pharmaceuticals, particularly antibiotics.

[0042] The wastewater treatment device 1 of this embodiment uses the titanium oxide-zeolite composite sheet 10, which allows for more efficient wastewater treatment than when titanium oxide powder, zeolite powder, or a titanium oxide sheet is used, and reduces the ecotoxicity of the treated water.

[0043] Furthermore, in the wastewater treatment device 1 of the present disclosure, the titanium oxide zeolite composite sheet 10 is attached to the outer surface of the cylindrical surface of the rotating drum 20, and ultraviolet rays can be irradiated in the atmosphere from directions including the direction perpendicular to the surface of the composite sheet 10. Therefore, even in a large device, the titanium oxide zeolite composite sheet 10 immersed in wastewater can be sufficiently irradiated with ultraviolet rays, and large amounts of wastewater can be treated efficiently.

[0044] The zeolite used in the titanium oxide-zeolite composite sheet 10 is preferably a high-silica zeolite. Specifically, the SiO2 / Al2O3 ratio is 50 or more and 200 or less.

[0045] The ultraviolet light sources 30, 31 to 35 are preferably arranged at multiple locations so that the titanium oxide-zeolite composite sheet 10 can be irradiated with ultraviolet light multiple times during one rotation of the drum while it is in the atmosphere, in order to promote multiple catalytic reactions in the organic matter adhering to the composite sheet 10.

[0046] The titanium oxide-zeolite composite sheet 10 can be produced using papermaking techniques by mixing titanium oxide powder, zeolite powder, fibers, binders, and the like. The titanium oxide-zeolite composite sheet 10 may contain titanium oxide powder, zeolite powder, and fibers. The titanium oxide-zeolite composite sheet 10 has water absorption properties. The titanium oxide-zeolite composite sheet 10 has a moderate amount of voids. Because the titanium oxide-zeolite composite sheet 10 is water-absorbent, wastewater containing organic matter is retained in the titanium oxide-zeolite composite sheet 10 even when the titanium oxide-zeolite composite sheet 10 is exposed to the atmosphere during rotation of the rotating drum 20. Furthermore, because the layer containing organic matter retained in the titanium oxide-zeolite composite sheet 10 is thin, ultraviolet irradiation allows the titanium oxide catalyst to function effectively.

[0047] The wastewater treatment method of the present embodiment is a method for treating wastewater containing organic matter using the titanium oxide-zeolite composite sheet 10, (a) immersing the composite sheet 10 in wastewater containing organic matter; (b) After step (a), ultraviolet light is irradiated onto the composite sheet 10 having moisture in the atmosphere from directions including a direction perpendicular to the surface of the composite sheet 10; (c) after the step (b), before immersing the composite sheet 10 again in the wastewater containing the organic matter, a step (c) of irradiating the composite sheet with moisture with ultraviolet light from a direction including a direction perpendicular to the surface of the composite sheet; Includes.

[0048] Some organic matter in wastewater can be transformed into harmless organic substances through multiple chemical reactions. In such cases, repeated exposure to ultraviolet light in the atmosphere can efficiently neutralize the wastewater containing the organic matter.

[0049] In addition, in the wastewater treatment method of this embodiment, the above steps (a) to (c) may be combined into one set, and the set may be repeatedly and continuously carried out. [Explanation of symbols]

[0050] 1 Wastewater Treatment Plant (RAOC) 1a Wastewater treatment equipment 10 Titanium oxide zeolite composite sheet 20 rotating drum 30, 31~35 UV light source 40 Motor 50 Tank

Claims

1. A treatment device for wastewater containing organic matter, a tank for storing wastewater; a composite sheet containing titanium oxide and zeolite; a rotating drum having the composite sheet attached to its surface, the rotating drum being arranged such that a portion of the surface of the composite sheet is immersed in the water and a portion is above the water surface when water is stored in the tank; a motor that rotates the rotating drum while maintaining a state in which a portion of the surface of the composite sheet is immersed in water and a portion is above the water surface with water stored in the tank; an ultraviolet light source that irradiates ultraviolet light onto the composite sheet on the water surface from a direction including a direction perpendicular to the surface of the composite sheet; A wastewater treatment device comprising:

2. The wastewater treatment device of claim 1 , wherein the composite sheet further comprises fibers.

3. The zeolite contained in the composite sheet is SiO ２ / Al ２ O ３ The wastewater treatment device according to claim 1 or 2, wherein the ratio is 50 or more and 200 or less.

4. A method for treating wastewater containing organic matter using a composite sheet containing titanium oxide and zeolite, comprising: (a) immersing the composite sheet in wastewater containing organic matter; After the step (a), a step (b) is performed in the atmosphere, irradiating the composite sheet having moisture thereon with ultraviolet light from a direction including a direction perpendicular to the surface of the composite sheet; After the step (b), and before immersing the composite sheet again in the wastewater containing the organic matter, a step (c) is performed in which the composite sheet to which moisture has adhered is irradiated with ultraviolet light from a direction including a direction perpendicular to the surface of the composite sheet; A method for treating wastewater, comprising:

5. The wastewater treatment method according to claim 4, wherein steps (a) to (c) are repeated.

6. A method for treating wastewater containing organic matter using a wastewater treatment device, comprising: A composite sheet containing titanium oxide and zeolite attached to the surface of a rotating drum is continuously rotated while a portion of the surface of the composite sheet is immersed in the wastewater and a portion is maintained above the water surface; While a specific portion of the composite sheet above the water surface is above the water surface and moisture is attached to the specific portion, ultraviolet light is irradiated multiple times from directions including a direction perpendicular to the surface of the composite sheet. Wastewater treatment methods.

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